Thank you @vieveda, that was a fun narrative!
Here are the new doors, inspiration from your words and Lewis Carroll:
After falling down a rabbit hole and drinking from a bottle labeled 'drink me', you find yourself shrunk down to six inches tall in a circular room filled with toys. Looking around, you see a large - relative to you, anyway - doll house set next to the table where you found the drink me bottle. At a loss for what else to do with your time here, you approach the building and realize there's something strange about this doll house. For one thing, it is built more like a castle than a house, with looming stone towers, sinisterly smiling gargoyles, and even a moat. You shiver at the eerie atmosphere and steel yourself as you continue toward the shadowy edifice.
When you finally reach the miniaturized castle - which takes a while, you being so small now - you are forced to stop at the edge of the moat. In front of your is a raised drawbridge leading to a castle gate. There is no way for you to tell what lies beyond - the walls of the castle are tall, and the flags flying from the ramparts are a simple purple with no symbols or words. Just as you start to sit down, tired from your journey across the room, a small head with bright orange hair made of yarn pops up at the top of the tallest tower.
"Hahahahahaha!" Cackles the ragdoll maniacally. "I'll let you in if you win!"
Win? Win what? Before you have a chance to ask, the doll continues.
"Guess my secret! Guess my secret!"
"Alright," you call up, because again, what else is there for you to do?
"Hee hee, hehe," giggles the doll, the sound raising gooseflesh on your arms. When it sings out its question, the words appear in a flash, hovering over the moat like someone had written them in giant - well, relatively giant - glowing script on the air itself.
"Answer quick, before the letters fade! Who did I rob of all their marbles, a cat, a hatter, or a jack of spades?"
What do you answer?
Cat
Hatter
Jack of Spades